Synthesis, Characterization, and Gas Permeation Properties

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41 Chapter 1 Although the thermal stability of the silylated derivatives of ethyl cellulose (2a–f), except 2f, is slightly lower than that of the starting material (1), it is still appreciably reasonable for practical applications as membrane-forming materials. Figure 3. TGA curves of polymers 1 and 2a–f (in air, heating rate 10 ºC min -1 ). Density and FFV of Polymer Membranes. Table 3 lists the van der Waals volume (υw), density (ρ), and fractional free volume (FFV) of the polymer membranes (1 and 2a–f). All of the silylated derivatives (2a–f) exhibited lower membrane density as compared to ethyl cellulose (1); e.g., the ρ value of 1 was observed to be 1.095 while those of 2a–f were in the range of 1.034–1.091. It was observed that an increase in the length of the alkyl chain in the silyl group led to a decrease in the density of the polymer membranes. Although silylation of ethyl cellulose resulted in the decreased density of polymer membranes, this decrease was counterbalanced by the increased van der Waals volumes of the silylated derivatives and resulted in net decrease in the FFV of 2a–f as compared to the starting polymer membrane (1). For instance, 2e exhibited the lowest value of fractional free volume (FFV is 0.148) in spite of its lowest density among all the silylated derivatives of ethyl cellulose (ρ is
Silylation of Ethyl Cellulose 1.034), which is probably due to its highest van der Waals volume. Gas Permeation Properties. The permeability coefficients of the membranes of polymers 1 and 2a–f to various gases measured at 25 °C are listed in Table 4, and their plot versus kinetic diameter of gases is shown in Figure 4. The gas permeability of the silylated derivatives was higher than that of ethyl cellulose, and Table 4. Gas Permeability Coefficients (P) of Polymer Membranes at 25 o C polymer Table 3. Physical Properties of Polymers 1 and 2a–f polymer T0 a ( o C) υw b (cm 3 /mol) ρ c (g/cm 3 ) FFV d 1 338 135.8 1.095 0.185 2a 280 152.1 1.076 0.180 2b 283 162.1 1.065 0.177 2c 305 159.0 1.067 0.178 2d 298 162.1 1.083 0.163 2e 273 183.8 1.034 0.148 2f 338 162.6 1.091 0.173 a Onset temperature of weight loss observed from TGA measurement in air. b υw: van der Waals volume. c ρ: density. Determined by hydrostatic weighing. d FFV: fractional free volume. Estimated from membrane density. P (barrer) a He H2 O2 N2 CO2 CH4 42 PCO2/PN2 PCO2/PCH4 1 53 76 18 5.0 110 12 22 9.2 2a 98 160 45 14 250 35 18 7.1 2b 81 130 42 13 230 33 18 7.0 2c 82 130 40 13 230 31 18 7.4 2d 67 100 27 8.0 150 18 19 8.3 2e 65 98 31 10 150 25 15 6.0 2f 58 86 23 7.0 130 15 19 8.7 a 1 barrer = 1x10 -10 cm 3 (STP) cm cm -2 s -1 cmHg -1 .
Page 1 and 2: Synthesis, Characterization, and Ga
Page 3 and 4: Table of Contents General Introduct
Page 5 and 6: General Introduction cellulose deri
Page 7 and 8: General Introduction biogenetically
Page 9 and 10: General Introduction chemistry offe
Page 11 and 12: General Introduction solution-diffu
Page 13 and 14: General Introduction A simplified t
Page 15 and 16: General Introduction been observed
Page 17 and 18: polymers. 41,46 General Introductio
Page 19 and 20: General Introduction Keeping in vie
Page 21 and 22: General Introduction the derivatize
Page 23 and 24: General Introduction strategy (G1-a
Page 25 and 26: General Introduction In conclusion,
Page 27 and 28: General Introduction 5. (a) Kobayas
Page 29 and 30: General Introduction 15. (a) Goetma
Page 31 and 32: General Introduction American Chemi
Page 33 and 34: General Introduction Macromolecules
Page 35 and 36: Silylation of Ethyl Cellulose Intro
Page 37 and 38: Silylation of Ethyl Cellulose milli
Page 39 and 40: Silylation of Ethyl Cellulose chlor
Page 41 and 42: Silylation of Ethyl Cellulose Resul
Page 43: Silylation of Ethyl Cellulose Solub
Page 47 and 48: Silylation of Ethyl Cellulose poly(
Page 49 and 50: Silylation of Ethyl Cellulose the r
Page 51 and 52: Silylation of Ethyl Cellulose D.; Y
Page 53 and 54: Chapter 2 51 Chapter 2 Synthesis, C
Page 55 and 56: 53 Chapter 2 are few and far betwee
Page 57 and 58: 55 Chapter 2 constant volume/variab
Page 59 and 60: 57 Chapter 2 Membrane Density. Memb
Page 61 and 62: 59 Chapter 2 IR spectrum of 1 (Figu
Page 63 and 64: 61 Chapter 2 1,3-bis(trifluoromethy
Page 65 and 66: 63 Chapter 2 The increase in the po
Page 67 and 68: 65 Chapter 2 other fluorinated poly
Page 69 and 70: 67 Chapter 2 of the gas permeabilit
Page 71 and 72: 69 Chapter 2 Gas Diffusivity and So
Page 73 and 74: 71 Chapter 2 mobility of the perflu
Page 75 and 76: 73 Chapter 2 1325-1329. (b) Hamza,
Page 77 and 78: Chapter 3 75 Chapter 3 Synthesis an
Page 79 and 80: 77 Chapter 3 cost, and above all ap
Page 81 and 82: 79 Chapter 3 molecular weights (Mn
Page 83 and 84: 81 Chapter 3 1.99-2.07 (m, 2H, (CH3
Page 85 and 86: 83 Chapter 3 25 °C, ppm): 11.9, 13
Page 87 and 88: 85 Chapter 3 38.1, 44.7, 46.8, 47.9
Page 89 and 90: 87 Chapter 3 CH2CH2C(=O)O), 2.50-4.
Page 91 and 92: 89 Chapter 3 1091, 1053, 853, 806,
Page 93 and 94: 91 Chapter 3 dendrons (G1-a-ІІ-G1
Page 95 and 96:
93 Chapter 3 (DMAP) as a base, as s
Page 97 and 98:
Figure 3. FTIR spectra of 1, 2c, an
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97 Chapter 3 (partly soluble) and 3
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99 Chapter 3 increased polarity of
Page 103 and 104:
101 Chapter 3 that of 1, and approx
Page 105 and 106:
103 Chapter 3 derivatization per th
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105 Chapter 3 (2a-c) were in the or
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107 Chapter 3 2709-2719. (b) Schenn
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109 Chapter 3 17. van Krevelen, D.
Page 113 and 114:
Chapter 4 111 Chapter 4 Synthesis,
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113 Chapter 4 Since, no significant
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115 Chapter 4 Materials. Ethyl cell
Page 119 and 120:
DStotal = DSEt + DSCarb (for 1a and
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119 Chapter 4 Figure 2. 1 H NMR spe
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121 Chapter 4 ruling out the possib
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123 Chapter 4 t-butyl moiety. A str
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125 Chapter 4 reported to lead to t
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127 Chapter 4 Table 4. Gas Permeabi
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129 Chapter 4 augmentation in eithe
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131 Chapter 4 indicate the signific
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133 Chapter 4 M.-R. J. Appl. Polym.
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Chapter 5 135 Chapter5 Synthesis an
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137 Chapter5 acid- and peptide-cont
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139 Chapter5 Specific rotations ([
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141 Chapter5 1.66 (brs, 1.1H, NHCH(
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143 Chapter5 as shown in Scheme 1,
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145 Chapter5 in Table 1. The molecu
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147 Chapter5 almost same pattern of
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Conclusions Table 3. Thermal Proper
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151 Chapter5 W.; Jing, X. J. Polym.
Page 155 and 156:
Chapter 5 Synthesis and Properties
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Acknowledgments While submitting th
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Synthesis, Characterization, and Ga
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